Berlin, Germany, Jan 16, 2008 / 11:33 pm (CNA).- Cardinal Karl Lehmann, head of Germany’s Catholic Bishops Conference, has announced his resignation as chairman of the conference for reasons of health, the Associated Press reports.

The 71 year-old Bishop of Mainz was elected head of the bishops’ conference in 1987, and had been re-elected for a six-year term in 2005.

"The recent appointments of new bishops has shown that it's time for a changing of the guard, it's time that a new generation takes over," Cardinal Lehmann wrote.

Observers consider Cardinal Lehmann, a close associate of his fellow German Pope Benedict XVI, to be a relatively liberal theologian.

Bishop of Aachen Heinrich Mussinghoff, deputy chairman of the German Bishops’ Conference, thanked the cardinal for his “unflagging service,” calling him "an excellent and reliable representative of the Church and its message."

Hans Joachim Meyer, of the Central Committee of German Catholics, said of Lehmann on Tuesday: "He has set standards through his actions, which will not be forgotten."

Cardinal Lehmann has been chairman of the German Bishops’ Conference longer than any other bishop.